Windfoil



FIG. 1 is a rear perspective view of the windfoil showing my new design;

FIG. 2 is a side elevational view thereof, the opposite side being a mirror image of the side shown herein;

FIG. 3 is a front elevational view thereof;

FIG. 4 is a top plan view thereof; and

FIG. 5 is a bottom plan view thereof. 

The ornamental design for a windfoil, as shown. 